All-optical Pattern Recognition Research Articles

Reconfigurable all-optical pattern recognition for PSK and QAM signals in high-speed optoelectronic firewalls.

In the fifth generation fixed networks (F5G) era, full-fiber-connected optical networks support emerging bandwidth-hungry services. However, optical networks are vulnerable to attack by tapping or other methods, which has been paid more and more attention in modern optical infrastructure. Therefore, high-speed optoelectronic firewalls appear as one of the promising technologies to guarantee security. The most significant and challenging component of a high-speed optoelectronic firewall is all-optical pattern recognition, especially for more advanced high-order modulation formats such as phase shift keying (PSK) or quadrature amplitude modulation (QAM) to satisfy efficient enhanced fixed broadband in F5G. In this paper, what we believe to be a novel reconfigurable all-optical pattern recognition system for PSK and QAM signals is proposed with two implementation architectures. The proposed system mainly consists of a generalized XNOR (GXNOR) and a recirculating loop. The two implementation architectures are precisely two realization methods of the GXNOR part. One employs two cascaded IQ Mach-Zehnder modulators and the other is implemented by the four-wave mixing. The numerical simulation results demonstrate that the two implementation architectures can both achieve all-optical pattern recognition for the reconfigurable high-order modulation formats of QPSK, 8PSK, and 16QAM with the recorded baud rate of 260GBaud.

Experimental demonstration of 84 Gbps QPSK signal’s 4-symbol all-optical pattern recognition

In the F5G era, a promising all-optical processing technology named all-optical pattern recognition has attracted more and more attention. Its applications include not only all-optical header recognition or address recognition in OCDMA but also optoelectronic firewalls. The higher the recognition rate of pattern recognition, the higher the processing rate of both applications can reach. To meet the development features of eFFB in F5G, high-speed all-optical pattern recognition should be achieved. In this paper, a QPSK all-optical pattern recognition system with a data rate of up to 84Gbps is proposed, analyzed, and experimentally demonstrated by employing commercial independent optical components. The system first converts the I branch of the input QPSK signal to a positive and a negative IM signal by adding the coherent carrier from the orthogonal polarization. Then the converted IM signals are coupled into time delay lines and optical AND logic gates implemented by HNLFs to achieve the optical correlation operation. In the end, a high-level optical pulse indicating the pattern recognized result is output. Numerical simulation results reveal that the proposed system can recognize the target sequence from the I branch of the input sequence and the position of the output high-level pulse in the time window of the I branch of the input sequence is the position of the last symbol of the target sequence. The results of the experiment demonstrate that the proposed system can recognize a 4-symbol target sequence from the I branch of an 8-symbol 84Gbps QPSK input sequence, which proves the all-optical pattern recognition of QPSK signals.

Structured light based optical pattern recognition:Principle and technical progress

<p indent=0mm>Optical image recognition technology has attracted considerable attention due to its advantages, such as extensive information processing capacity, high-speed calculation, and advanced parallel processing. This technology also has various applications in security systems, remote sensing imaging, biomedical technology, and military scenarios. With the development of structured optical engineering technology, optical image recognition has gained new vitality in recent years. This paper describes two major optical image recognition correlators, the Vander Lugt Correlator and Joint Transform Correlator. We describe the progress of research on optical pattern recognition in the framework of linear optics, nonlinear optics, and quantum correlation. Our study also emphasizes how structured light engineering technologies can be incorporated into all-optical pattern recognition systems to accelerate technological developments.

All-Optical Pattern Recognition and Image Processing on a Metamaterial Beam Splitter

Recognition, comparison, and analysis of large patterns or images are computationally intensive tasks that can be more efficiently addressed by inherently parallel optical techniques than sequential electronic data processing. However, existing all-optical image processing and pattern recognition methods based on optical nonlinearities are limited by an unavoidable trade-off between speed and intensity requirements. Here we propose and experimentally demonstrate a technique for recognition and analysis of binary images that is based on the linear interaction of light with light on a lossy metamaterial beam splitter of substantially subwavelength thickness. Similarities and differences between arbitrarily complex binary images are mapped directly with a camera for real-time qualitative analysis. Regarding quantitative analysis, agreement, disagreement, and any other set operation between the patterns can be determined from power measurements acquired with a photodetector. In contrast to nonlinear technique...

High-speed all-optical pattern recognition of dispersive Fourier images through a photonic reservoir computing subsystem.

In this Letter, we present and fully model a photonic scheme that allows the high-speed identification of images acquired through the dispersive Fourier technique. The proposed setup consists of a photonic reservoir-computing scheme that is based on the nonlinear response of randomly interconnected InGaAsP microring resonators. This approach allowed classification errors of 0.6%, whereas it alleviates the need for complex high-cost optoelectronic sampling and digital processing.

All-Optical Header Processing in a 42.6 Gb/s Optoelectronic Firewall

A novel architecture to enable future network security systems to provide effective protection in the context of continued traffic growth and the need to minimize energy consumption is proposed. It makes use of an all-optical prefiltering stage operating at the line rate under software control to distribute incoming packets to specialized electronic processors. An experimental system that integrates software controls and electronic interfaces with an all-optical pattern recognition system has demonstrated the key functions required by the new architecture. As an example, the ability to sort packets arriving in a 42.6 Gb/s data stream according to their service type was shown experimentally.

All-fiber joint-transform correlator for time-multiplexed signals

We present the temporal counterpart of a spatial joint-transform correlator. This system optically measures the rf spectrum of a real-time spectral interferogram achieved by stretching a sequence of two time-multiplexed pulses. The optical rf analyzer makes use of the cross-phase modulation on a cw probe in a highly nonlinear fiber. We show that the optical spectrum appearing on the cw signal contains the information of the electric-field cross correlation of the signals under test. This device offers potential applications for all-optical pattern recognition of ultrashort pulses.

All-optical pattern recognition for digital real-time information processing.

To recognize digital streams of digital data, all-optical and passive techniques able to discriminate optical bit words in real time are presented. Discrimination capability of different correlators, both in free space architectures and in delay lines structures, is theoretically and experimentally analyzed. Experimental performances in word recognition are shown in the case of a volume holographic correlator, in the case of a lithographic phase-only-filter correlator, and in the case of a novel coherent delay lines correlator operating at the wavelength 1550 nm and at the bit rate of 2.5 Gbit/s.

Optical pattern recognition by use of a segmented semiconductor optical amplifier

A technique for high-speed, all-optical pattern recognition based on cross correlation in a segmented semiconductor optical amplifier (SSOA) is presented. A counterpropagating pump-probe setup is used to perform cross correlation of the spatial gain-loss pattern in the SSOA with the optical data pattern (pump), and the result is read out with a counterpropagating probe. Cross correlation of 4-bit patterns at 85 Gbits/s is experimentally demonstrated. Simulations show reasonable agreement with experimental measurements and are used to address scalability to higher bit rates and longer data patterns.